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pay attention on TN11SCC Failure to Restart from a Power Outage in OptiX OSN 6800

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pay attention on TN11SCC Failure to Restart from a Power Outage in OptiX OSN 6800

Summary:
There is a small probability that TN11SCC boards equipped with memory chips of a specific lot fail to restart from a power outage.[Problem Description]Trigger condition:
1. A TN11SCC board uses a memory chip of a specific lot.2. The TN11SCC board experiences a power outage (for example, the board is removed and reinserted, or the subrack is powered off).
Symptom:
An OSN 6800 NE is unreachable by the NMS. As confirmed onsite, after the TN11SCC board on the NE is powered on again, the STAT indicator fast blinks green and the PROG indicator fast blinks red at the same time on the front panel of the board. The board fails to restart.Identification method:
A TN11SCC board has the problem described in this notice when the following conditions are met:
1. An abnormality occurs after the SCC board or the subrack is powered on again from a power outage.
2. The BOM number of the TN11SCC board is included in the attachment of this notice.[Root Cause]
The TN11SCC boards use memory chips of a specific lot which have a bug. Due to this bug, electrical discharging inside the chips upon board power outage causes a chip failure. Consequently, the boards fail to restart. The following table provides statistics on the failure rates for different working durations of the boards.

Working Duration (Year)

Chip Failure Rate

2

0.002%

3

0.67%

4

1.58%

5

2.61%

6

3.73%

7

4.90%

8

6.11%

9

7.73%

10

8.65%

[Impact and Risk]
1. If the TN11SCC board is removed and reinserted, there is a small probability that the TN11SCC board fails to restart and the NE is unreachable by the NMS.
2. If the NE is powered off and then powered on again, there is a small probability that the TN11SCC board on the NE fails to restart and consequently services are interrupted.[Measures and Solutions]Recovery measures:
If an Huawei optical transmission OSN 6800 NE needs to be powered off and powered on again (for example in a subrack power supply cutover scenario), backup the NE database and prepare SCC spare parts as follows:
1. For a TN11SCC board of a version earlier than V100R004C04SPC800, prepare a spare TN11SCC board of the same software version.
2. For a TN11SCC board of V100R004C04SPC800 or a later version, prepare a spare TN11SCC or TN52SCC board of the same software version.
When the TN11SCC board on the OSN 6800 NE fails to restart from a power outage, replace the board with the prepared spare part in a timely manner and restore the NE database using the backup database.Workarounds:
None.
Preventive measures:
Replace involved TN11SCC boards.
Material handling after replacement:
Send the replaced TN11SCC boards back to Huawei HQ for chip repair